Perforating die



9 936- c. s. KNIGHT PERFORATING DIE Filed Sept. '29, 1954 2 Sheets-Sheet 1 TTORNE ZEBQQSH g wfifl 28 E1936. c. s. KNIGHT PERFORATING DIE 2 Sheets-Sheet 2 Filed Sept. 29, 1934 'ATTORNEK Patented Apr. 28, 1936 PATENT OFFICE PERFORATING DIE Chesterton S. Knight, Brockton, Mass., assignor to Geo. Knight & Co. Inc., Brockton, Mass., a corporation of Massachusetts Application September 29, 1934, Serial No. 746,090

5 Claims. (01. 164-88) This invention relates to perforating dies of the type used extensively in the shoe industry for the purpose of ornamenting parts of the uppers of shoes, it being understood, however, that such dies are not limited to use in this particular industry.

As commonly constructed, a die of this character comprises a series of punches, usually of tubular form, mounted in a base, and a stripper plate supported on springs and apertured to permit the passage therethrough of the punches. In using one of these dies the die structure is placed in a press having a reciprocating head, the work is properly positioned on the stripper plate, and the press then is tripped, whereupon the head comes down and forces the leather downwardly upon the punches, causing them to perforate the work. As soon as the head of the press rises, the stripper plate forces the leather upwardly and removes it from the punches, after which the work is taken out of the machine.

It is customary to make these dies individual to the article of work to be operated upon. Usually this is necessary because of the nature of the work to be done. When, however, it is desired to perforate some relatively large section of work, such as a shoe vamp, or a glove trank, with a design that extends over substantially the entire area of the piece, the expense of manufacture of the die required for this purpose becomes extremely high because of the great number of punches that must be used in it. If, in addition, the punches are located so close to each other that a stripper plate cannot be used because there is not room within which to locate the springs required to lift the plate, then the difiiculty of using such a die is greatly increased because the stripping operation must be performed by hand. Furthermore, a much heavier press than that ordinarily employed for this kind of work usually is required in perforating these large pieces of leather. Conditions of this character are encountered rather commonly in the manufacture of certain grades of women's shoes, gloves, and leather specialties, more especially in those cases in which the elements of the design are very simple but are repeated at closely spaced intervals to produce an all-over perforated pattern.

The present invention is especially concerned with the problems presented by these conditions, and it aims to devise a thoroughly practical solution for them.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

In the drawings,

Figure 1 is a plan view of a perforating apparatus or mechanism constructed in accordance with this invention;

Fig. 2 is a side elevation of the mechanism shown in Fig. 1;

Figs. 3 and 4 are vertical, sectional views approximately on the lines 33 and 4-4, respec- 10 tively, Fig. 1;

Fig. 5 is a perspective view of the construction illustrated in Fig. 1;

Fig. 6 is a vertical, sectional view through one of the work holding devices; and 15 Figs. 7 and 8 are plan views illustrating different perforated patterns.

The construction shown in the drawings comprises a die, indicated in general at 2, and which may be made in accordance with prior practices except that instead of being shaped to conform to the contour of the shoe quarter, vamp, or other part to be perforated, it is made in the form of a relatively long and narrow strip. The length of the die is greater than the width of the work to 25 be perforated on it, and the width is determined by the nature of the design or pattern to be made. As best shown in Fig. 3, this die structure includes a main base plate 3 on which is removably supported a supplemental base 4 carrying a series of perforating punches 5 of the usual tubular form. A stripper plate 6 is removably set into a table 1 which cooperates with the stripper plate to support the work W, both the stripper plate and the table being mounted on spiral 35 springs 8 in the usual manner. Some of these springs encircle the usual guide posts 9.

Mounted on the table 1 is a slide I0 which is guided by a bar I2, forming one element of the table, for reciprocating movement in a straight line toward and from the die 2. This slide carries work holding devices which, in the particular form shown, consist of two pairs of spring fingers l3 and M, respectively, projecting backward from the opposite margins of the slide, and 45 a work clamp l5 mounted directly on the slide. At its rearward edge the slide is provided with a series of teeth or short spurs projecting upwardly therefrom, as best shown at IS in Figs. 5 and 6, and the clamp l5 consists of a metal plate arranged to rock up and down loosely on rivets I'I, this plate being provided at its rearward edge with holes l8 registering, respectively, with the spurs l6. Consequently, by placing an article of work, such as the vamp W shown in Fig. 1, on

the table, locating its forward margin between the rearward edges of the slide l0 and clamp l5, and then forcing this clamp down, the spurs may be forced into or through the leather sufficiently to fasten the work securely in the clamp. A latch 20, pivoted at 2| on the clamp l5, and having two fingers 22 projecting downwardly through openings in the slide and bent forwardly to extend under the slide, as shown in Fig. 6, is provided to lock the plate [5 in its work clamping position. This latch also is equipped with a U-shaped releasing member 23 by means of which it may be swung forward to unlock the plate l5 and permit this plate to be tipped upwardly to release the work. After the work has been secured to the slide in this manner, it is smoothed out on the table and its opposite margins may be slipped under or between the spring fingers l3 and 14 which help to hold the work in a flat and smooth condition. When the work has been so secured, the operator may slide the work backward and forward across the surface of the die strip 2 simply by moving the slide 10.

A spacing mechanism also is provided to cooperate with the slide in predetermining the lengths of successive work feeding movements and to lock the slide, and therefore the work, in different operative relationships to the die. It will be observed that the bar i2 has a series of holes 24 drilled through it at accurately spaced distances, the distance between adjacent holes throughout the lengthof the bar being uniform. The slide includes a guide block 25, Fig. 4, the upper surface of which is grooved to take the bar I2, this guide block being secured rigidly to the plate II] which forms the main body of the slide. The spacing device comprises a yoke including two pins 26-26 and a. cross bar 21 connecting them and located above the slide, and another cross bar 28 also connecting the pins and located below the slide, the latter bar being secured to the pins 26-26 by screws 30-30. This yoke straddles the bar I2, is carried by the slide, and itself carries a locking pin 3| which is riveted to the bar 28, slides in a vertical hole formed in the block 25 and has a tapered upper end to fit snugly in the holes 24 in the bar I 2. Two coiled springs 32-32 encircle the pins 26-26 and serve to hold the yoke normally in a raised position in which the pin 3| is entered in one of the holes 24.

It will be evident that by depressing the bar 21 the pin 3| will be forced down below the bar l2, thus unlocking the slide from the bar and permitting it to be moved either toward or from the die. If the cross bar 21 is released so that the pin rides along the lower surface of the bar I2, it will snap into the next hole 24 and the operator then knows that he has moved the work a distance equal to the distance between the centers of the holes 24.

In using a die of this character, the entire die structure is placed in a suitable press, with the base 3 resting on the lower platen of the press. The operator places a piece of work on the table, secures it in the holder, as above described, and then moves the slide l0 backward until the forward margin of the vamp or other article of work is located on the stripper plate 6 and in proper position to be perforated. He then trips the press, whereupon the movable presser head 33, Fig. 3, comes down and forces the work down upon the punches 5 far enough to cause them to cut entirely through the leather. Usually a sheet P of paper, fiber, or equivalent sheet material, is placed between the upper surface of the work and the lower surface of the reciprocating head 33 so that the ends of the tubes or punches 5 do not out against the metal surface of the head but against the surface of the interposed paper sheet. The presses used for this purpose customarily are equipped with means for supporting and feeding a web of paper into position for the perforating operation. The forward margin of the work now having been perforated across substantially its entire width, the operator depresses the cross bar 2'! of the locking mechanism and moves the slide I3 and the work W forward until the locking pin 3| snaps into the next hole 24. He then trips the press again, thus perforating another section of the work. He repeats these operations, feeding the work step by step and perforating between feeding movements, until the entire length of the work has been perforated. These feeding movements are so predetermined in length by the spacing of the holes 24 that each successive section of the work positioned on the die for the perforation operation will be so registered with the die that the sections perforated at successive operations will match with each other and form an all-over perforated pattern exactly as would be produced with a single die large enough to perforate the entire vamp or other article of work at one operation.

When the perforating process has been completed on a given piece of work, the slide If] is withdrawn, the completed article is removed from the work holders, a new one is introduced in its place, and the operations above described are repeated.

The invention effects a great saving in initial expense as compared to that involved in making a die of the usual form required for perforating an all-over design on vamps, quarters, and other of the large pieces of work. In addition, it makes it possible to perforate such work in the presses ordinarily used for this purpose, and it has the further, and extremely important, advantage of performing the stripping operation automatically and in the manner common heretofore in operating on small pieces of work. This result is made possible by virtue of the fact that the design can readily be produced in sections if the work feeding movements are controlled with sufficient accuracy so that the design produced in each successive perforating operation will match or register properly with that made in the next preceding perforating step. This is readily possible in such patterns as those shown in Figs. 1, '7 and 8 in which the design involves repeats spaced apart by relatively small distances. But the same process can be used in a wide range of other designs.

It will be understood that the length of the die strip will be determined by the width of the area to be perforated, and that the width of the die strip will depend partly upon the nature of the design, and partly, also, on the requirements of the die structure. In other words, there is a practical limit to the number of tubes which can be used in such a structure economically, and a much more limited range in the width of the stripper plate that can be used between adjacent spring supports and still make the plate perform its stripping function satisfactorily. Because of the fact that this die does not conform to the outline or shape of the article of Work to be perforated, it is entirely feasible to use the same die in operating on toe caps, vamps and quarters of shoes, for example, instead of requiring dies individual to these parts, as has been necessary heretofore.

While I have herein shown and described a typical embodiment of my invention, it will be understood that the size, shape and character of the punches necessarily will depend upon the requirements of individual designs and that various other changes will necessarily be made in accordance with the nature of individual kinds of work. Consequently, the invention may beembodied in other forms than that specifically shown While still retaining its essential spirit and its fundamental characteristics.

Having thus described my invention, what I desire to claim as new is:

1. In a machine for perforating articles of leather, the combination of a perforating die strip including a set of sharp edged punches and a stripper operatively associated with them, of means for backing up the work while said punches pierce it and for operatively supporting a sheet of paper for said punches to out against, and means operable to feed the work in steps of predetermined length across the surface of said stripper plate and to register successive portions of the work with the die to cause successive sections of the work perforated by said die to match with each other.

2. In a perforating mechanism of the type comprising a perforating die strip including a set of punches, means for operatively supporting them and a stripper plate operatively associated with said punches, the combination with a slide, work holding devices carried by said slide, means supporting said slide for reciprocating movement in a fixed path to carry the work across said plate, and means for locking said slide in a series of positions along said path, said positions being spaced apart by equal distances.

3. In a perforating mechanism of the type comprising a perforating die strip including a set of punches, means for operatively supporting them and a stripper plate operatively associated with said punches, the combination with a work supporting table forming, in effect, a continuation of said stripper plate, means cooperating with said table for holding the work in a straightened and smoothed condition on said table, devices supporting said means for movement to feed the work in a fixed path across the surface of said plate, and parts cooperating with said means and said devices to predetermine the length of the successive work feeding movements, whereby the designs perforated in successive sections of the work by said die will be properly matched with each other.

4. In a perforating mechanism of the type comprising a perforating die strip including a set of punches, means for operatively supporting them and a stripper plate operatively associated with said punches, the combination with a work supporting table forming, in effect, a continuation of said stripper plate, a slide, work holding means carried by said slide, said slide being mounted on said table for movement in a fixed path to position different sections of the work to said die for its operation thereon, and means for locking said slide in different work positioning relationships to said die.

5. In a perforating mechanism of the type comprising a perforating die strip including a set of punches, means for operatively supporting them and-a stripper plate operatively associated with said punches, the combination with a work supporting table forming, in effect, a continuation of said stripper plate, means cooperating with said table for holding the work in a straightened and smoothed condition on said table, devices supporting said means for movement to feed the work in a fixed path across the surface of said plate, and spacing mechanism cooperating with said means and devices to predetermine the lengths of successive work feeding movements and to lock said means at the end of said feeding movement and in position for the respective perforating operations on a given piece of work.

CHESTERTON S. KNIGHT. 

